Rotterdam harbor -- where world's freighters and tankers drop anchor

A small boat swings out into Rotterdam's seaport, past tall cargo-handling cranes, and down one of many channels. "Look over here," a guide says. He points to a tall and long supertanker unloading Middle Eastern oil. High above the water, the ship's curving side looms over the tiny craft. The shipmates look almost straight down, and wave.

The air is speared with bristling masts, floating derricks, and carriers used for lifting and stacking 20- and 40-foot containers. Cranes unload foodstuffs and fat rools of newsprint.

Sights of a grand scale are common in the world's largest port, where even a 2 1/2-hour tour covers only about half of it. Lately, Rotterdam port officials have had so many requests for visits that they no longer give tours of the entire port.

World attention has been focused on Rotterdam in recent years for two reasons:

* It is the heart of the sometime-mysterious oil "spot market," where dealers buy and sell huge quantities of petroleum not already under contract to customers.

* Even though Rotterdam can claim to be the world's largest port -- more than twice as bis as the second largest one in Kobe, Japan -- it has begun expansion plans that will further widen its lead.

The port's Europe Container Terminal will be expanded under a $158 million ( 400 million dutch guilders) project, according to Jan Riezenkamp, a Rotterdam alderman and head of the city council's port and economic development panels.

That project comes on top of previously announced plans to build a $125 million (300 million guilder) oveflow port on the Maasvlakte, a 6,155-acre section of land reclaimed from the sea at the mouth of the River Rhine, the entrance to Rotterdam's harbor.

At Maasvlakte, in waters as deep as 60 feet, a six-mile wall of huge concrete blocks, with the help of tons of sand and boulders, holds back the persistent North Sea.

Last year Rotterdam handled more than 1.2 million containers, making it by far the largest container port in Europe. By 1985 it expects to handle nearly 1 .7 million boxes.

And as Europe continues to switch its power plants from oil to coal, the port's expansion plans call for keeping its leadership position in coal-handling capacity, feeding even more of the black fuel up the Rhine to West Germany's industrial heartland.

Making additional use of the Maasvlakte, a consortium of six companies is building a $83 million (200 million guilder) coal terminal that will boost Rotterdam's annual capacity from 11.4 million metric tons in 1980 to some 25 million tons by the end of the decade. The investors include British Petroleum, Esso, Shell, a Dutch trading group, a West German utility, and one of Rotterdam's largest stevedoring firms.

The three oil companies in the group help give Rotterdam another distinction: It is the only seaport with five oil refineries. Chevron and Gulf also have refineries here. And since the Iran-Iraq war destroyed what was the world's largest refinery at Abadan, Iran, the Shell facility in Rotterdam is the world's largest.

The city's location at the mouth of the Rhine and Maas rivers, its proximity to major European markets, and the Dutch tradition as a nation of international traders give Rotterdam built-in advantages.

It was from the old port of Delfshaven, near the center of Rotterdam, that ships left Holland for the New World in 1620. Today, that area is filled with pleasure boats.

Further out, special ramps for "ro-ro" ships stand waiting for roll-on, roll-off cargo, including cars, trucks, and "anything that can be put on wheels, " says port spokesman Wil van Oosterhout.

Farther out in the harbor, the ships are bigger, carrying coal, iron ore, and sand. Finally, the supertankers head for the refineries and the sprawling tank farms.

Rotterdam has captured about 45 percent of all port traffic handled in its competitive region between Hamburg and Le Havre. Last year Rotterdam moved over 300 million tons of cargo, carried in and out by more than 30,000 vessels using the 35-kilometer channel that stretches from Hook of Holland to Rotterdam.

Since World War II Rotterdam has not only rebuilt its port, it has added three new land areas. Before the Maasvlakte, completed in 1974, the Botlek was added in 1957 and the "Europoort" was added 1968. Each of these areas could be a medium-sized ports in themselves.

Beyond the development of the Maasvlakte's coal and container capacity, Rotterdam's plans call for expansion through the year 2000, but not at the pace of recent years. For instance, plans for a new port basin have been dropped.

The port's rebuilding and size give officials a sense of pride. "We are not a Dutch port," Mr. Rienzenkamp contends. "We are a European port. We are the largest German port."

Adds Mr. Van Oosterhout with a hint of jesting: "Rotterdam is a po rt with a city."